A023591 - OEIS

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A023591

Greatest exponent in prime-power factorization of 2*prime(n)+1.

2

1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 3, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 3, 1, 1, 1, 1

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OFFSET

1,6

LINKS

Table of n, a(n) for n=1..99.

FORMULA

a(n) = A051903(A072055(n)). - Amiram Eldar, Sep 09 2024

MAPLE

A023591 := proc(n)

A051903(2*ithprime(n)+1) ;

end proc: # R. J. Mathar, Jul 08 2015

MATHEMATICA

a[n_] := Max[FactorInteger[2*Prime[n] + 1][[;; , 2]]]; Array[a, 100] (* Amiram Eldar, Sep 09 2024 *)

PROG

(PARI) a(n) = vecmax(factor(2*prime(n)+1)[, 2]); \\ Michel Marcus, Apr 20 2021

CROSSREFS

Cf. A051903, A072055.

Sequence in context: A030348 A143811 A109673 * A165661 A107711 A242345

Adjacent sequences: A023588 A023589 A023590 * A023592 A023593 A023594

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved